Simon is a young man in his twenties who uses his short stature and boyish appearance to avoid the Confederate army, making a living as an independent fiddler. Fiercely protective of his freedom, he is hot-tempered but deeply driven to build a stable life, motivated in part by his abandonment by his roaming fiddler father. His musical talent allows him to communicate and connect with others when his prickly personality falls short.

Doris is a young, intelligent Irish immigrant who works as an indentured governess for the Webb family. Described as delicate and small in stature, she has a deep appreciation for the natural beauty of Texas and its wildlife. Despite facing cruel treatment from her employers, she maintains a gentle nature and uses her musical abilities on the piano to find moments of peace.

Damon is a middle-aged, eccentric former university professor who plays the tin whistle in Simon's makeshift band. He frequently quotes Edgar Allan Poe and retains a kind, patient demeanor despite suffering from an old hand injury that limits his playing. He serves as a mature, steadying presence for the younger musicians as they travel.

Colonel Webb is an imposing, volatile, and controlling Union officer. He commands his household through intimidation and holds Doris under a strict indentured labor contract. He weaponizes his social standing to exert dominance over others, viewing both his family and his staff as subjects to be strictly managed and punished.

Doroteo is a Tejano guitar player originally from the dangerous Nueces Strip. He joined the army impulsively after a romantic quarrel but now travels with the band, bringing a playful energy to the group. He speaks fluent Spanish and English and often takes on a protective, older-brother role toward the youngest band member.

Patrick is a thirteen-year-old Irish immigrant who plays the bodhran for the band. Small and youthful, he provides the rhythmic backbone for their music and serves as the social glue that keeps the disparate men together. His status as a fellow Irish immigrant provides Simon a convenient excuse to initiate a correspondence with Doris.

Lester Pruitt is a crude, untrustworthy musician who joins Simon's band in San Antonio. He is astonishingly profane, lacks personal hygiene, and struggles to play the fiddle, though he can manage the bodhran. His impulsive and aggressive behavior constantly threatens to cause trouble for the rest of the band.

Mrs. Webb is the wife of Colonel Webb. She is often caught in the crossfire of her husband's volatile temper and shares in the family's harsh treatment of their governess, Doris, occasionally mocking the young woman's interests and natural wonder.

Josephine is the fourteen-year-old daughter of the Webb family. Raised in a tense household, she acts out by complaining frequently and reporting on Doris's activities to her father, despite Doris's attempts to befriend and help her.

Mercedes is the Mexican maid working for the Webb household in San Antonio. She befriends Doris and becomes a vital secret ally, helping pass letters and messages between Doris and Simon to evade Colonel Webb's strict rules.

Solomon Bradford is an elderly landowner originally from West Virginia. His mind is fading and he often appears confused, making legal or business discussions difficult until Simon uses traditional music from his home state to help clear his memory.

Jacob Whittaker is a Union military man stationed in San Antonio. He observes the growing connection between Simon and Doris and acts with honor to assist them in working within the strict military laws governing the city.

Miss Pryor is the daughter of an affluent household who hires Simon's band. Confident in her social standing and wealth, she attempts to bring Simon into her employment as a music tutor, offering him a comfortable life in St. Louis which he politely rejects.

Mr. Twohig is a successful Irish immigrant banker in San Antonio. He manages Simon's accounts and provides a safe, respectable environment where Simon and Doris can play music and speak openly away from the dangerous Webb household.

Walking David is Simon's elderly uncle who raised him after his mother died of cholera. He provided the only stable familial presence in Simon's chaotic early life.

Henri Boudlin is Simon's absent father, a roaming fiddler who left Simon's mother before they were married. His inconstancy drives Simon's fierce desire to be a dependable, stable partner.